Extraction of &#947-oryzanol from rice bran Extração de γ-oryzanol de farelo de arroz

&#947;-oryzanol, a phytochemical, has antioxidant activities and potential health benefits. In this study, we aimed to develop a method for extracting high amounts of &#947;-oryzanol from rice bran and for verifying its stability in different solvents. Of the 5 methods under investigation, the one that yielded the highest &#947;-oryzanol content was further improved by using a central composite rotational design (DCCR - 2(4), including 8 tests in axial conditions and 4 central points, totaling 28 trials). The parameters under study were temperature, time, volume, and the ratio of hexane:isopropanol. High &#947;-oryzanol content (13.98 mg.g-1) was obtained by using the following extraction conditions: 40° C, 40 min, and 75 mL hexane:isopropanol (1:3). The limits of detection and quantification of the method were 0.9 µg g-1 and 31 µg g-1, respectively. The instrumental precision was 0.004%, the repeatability (CVr) was 9.4%, and the recovery was 111.7 ± 17.7%. &#947;-oryzanol is more stable in isopropanol than in hexane, in which 100% concentration could be maintained after refrigeration for 72 days.<br>&#947;-orizanol, um fitoquímico, tem atividade antioxidante e benefícios potenciais para saúde. Esse estudo objetivou desenvolver um método para extração de alta quantidade de &#947;-orizanol de farelo de arroz e verificar sua estabilidade em diferentes solventes. Dentre os cinco métodos estudados, o que teve maior rendimento em &#947;-orizanol foi melhorado, usando um delineamento composto central rotacional (DCCR - 2(4), incluindo 8 experimentos no ponto axial e 4 no ponto central, totalizando 28 experimentos). As variáveis testadas foram temperatura, tempo, volume e proporção de hexano: isopropanol usados na extração. Elevado conteúdo de &#947;-orizanol (13,98 mg g-1) foi obtido quando as condições de extração foram 40° C, 40 min e 75 mL de hexano:isopropanol (1:3). Os limites de detecção e quantificação do método foram 0,9 µg g-1 e 31,0 µg g-1, respectivamente. A precisão instrumental foi 0,004%, a repetibilidade (CVr) 9,4% e a recuperação 111,7 ± 17,7%. &#947;-orizanol é mais estável em isopropanol do que em hexano, onde 100% da concentração foi mantida após refrigeração por 72 dias

Assessment of nevirapine prophylactic and therapeutic dosing regimens for neonates

Background: Nevirapine (NVP) is a key component of antiretroviral prophylaxis and treatment for neonates. We evaluated current World Health Organization (WHO) weight-band NVP prophylactic dosing recommendations and investigated optimal therapeutic NVP dosing for neonates. Methods: The PHPT-5 study in Thailand assessed the efficacy of "Perinatal Antiretroviral Intensification" to prevent mother-to-child transmission of HIV in women with 0.10 mg/L) and for therapeutic efficacy (>3.0 mg/L) using different infant dosing strategies. Results: Sixty infants (55% male) were included. At birth, median (range) weight was 2.9 (2.3-3.6) kg. NVP concentrations were best described by a 1-compartment PK model. Infant weight and postnatal age influenced NVP PK parameters. Based on simulations for a 3-kg infant, >= 92% would have an NVP trough >0.1 mg/L after 48 hours through 2 weeks using the PHPT-5 and WHO-dosing regimens. For NVP-based therapy, a 6-mg/kg twice daily dose produced a trough >3.0 mg/L in 87% of infants at 48 hours and 80% at 2 weeks. Conclusion: WHO weight-band prophylactic guidelines achieved target concentrations. Starting NVP 6 mg/kg twice daily from birth is expected to achieve therapeutic concentrations during the first 2 weeks of life